Current outboard motors or engines employed in relation to marine vessels typically employ an engine coupled to a leg system that mounts the engine and constrains the engine above the water's surface and a 90° gear case below the water surface. The engine shafting transmits torque that is downwardly directed to the 90° gear case which in turn supports a propeller for the creation of horizontal thrust to propel the attached watercraft. As such current outboard motors have a cowling system that surrounds the engine on all sides thus encasing it and protecting it from the environment. One of the significant functions of an outboard motor (or engine) cowl is to provide or facilitate airflow to the enclosed engine and throttle at relatively low restriction to allow for engine operation and prevent/minimize loss of horsepower due to inadequate air flow.
Although the cowling system of an outboard motor must be capable of allowing the passage of air to the engine in order to support combustion, this airflow into the cowling can be challenging as the air can be carrying large amounts of entrapped moisture and or liquid water into the engine compartment. Indeed, a complication associated with providing air to the engine is that typically the air provided to the engine is from the outside environment of the motor, which is in direct proximity to water of a body of water in which the motor is operating, such that the air entering the motor usually (if not always) includes along with it some amount of water that is entrapped/entrained with the air. Indeed, an outboard motor can be subjected to following waves of water that can cover the cowling system with water and result in significant water entering into the outboard motor and, regardless of wave levels, rain water or splashing from the ocean can present liquid water to the cowl air inlet system. As the engine is enclosed by the cowl system, once water enters the cowl it is important that the water be prevented/hindered from entering the engine intake system to avoid negative effects upon the engine by the ingress of water.
In view of the above, outboard cowling systems such as a cowling system 5200 shown in FIG. 52 (Prior Art) are typically carefully designed to minimize inbound water while at the same encouraging airflow to the engine less power losses occur due to intake air restrictions. Thus an air entrance area (air intake) 5202 is normally located high on the cowling system along an upper cowling portion 5206, far from the water's surface (and above a lower cowling portion 5208), as determined in part by an arrangement of an upper cover section 5210 along the upper cowling portion 5206. With such an arrangement, the cowling system 5200 is fashioned in a manner to accept air via an air flow path (or paths) 5212 that particular involves passage of air but discourages the entrance of liquid water. Further, normally upwardly-looking air passages 5204 are projecting above an internal surface 5214 and are covered from above by the upper cover section 5210 to prevent/hinder direct ingress of water into the outboard motor, as shown. A further development in conventional cowl systems is the inclusion of an inner liner system that controls entering air and directs it downwardly to the bottom cowl (lower cowling portion 5208, which is located above a leg system 5218 of the outboard motor) where the air/moisture is then released into the cowling system. In this manner the downward path of the air inside the liner is done to direct extra water down to the lower cowl where drains are included to release the water to the body of water (e.g., ocean) while air is allowed to rise thru the engine compartment (inside space for the engine) 5216 for the engine air intake.
Both of the above-described systems have proven to be effective for various sizes of outboard motors with engines up to and including 350 horsepower (hp) engines. However, as increased power is accompanied by increased airflow, these types of intake systems become spatially inadequate to provide large amounts of airflow within the compact space of the cowling system without creating large airflow restrictions in order to accomplish the necessary separation of air from water.
In addition to the above concerns, in today's current inboard and stern drive marine propulsion systems, two types of water pumps are used. First a sea pump lifts water from the ocean and provides it to the engine where a circulation pump then in turn circulates water continuously thru the engine block and heat system. The sea pump is normally rubber belt driven from the crankshaft with external water hoses connecting to the drive apparatus where water is picked up and returned to. The sea pump is typically (if not always) composed of a multivane flexible polymer impeller which has a positive displacement feature at low speed and starting for priming functions and transitions to a centrifugal pump at speed as the polymer vanes loose contact with the liner at higher speeds. The circulation pump is typically (if not always) of rigid centrifugal impeller construction and is attached to the engine and also rubber belt driven from the crankshaft.
Such sea and circulation pumps operate efficiently together and as such are widely used both in open cooling systems where sea water is the only coolant utilized and in closed coolant systems where sea water is circulated by the sea pump thru heat exchangers while the circulation pump circulates coolant (glycol types) thru the engine and heat exchanger (much like an automotive system if the radiator were replaced with a water to water heat exchanger for the sea pump to push sea water through).
Notwithstanding the practicality of such existing arrangements, such water pump arrangements in outboard motors nevertheless have some disadvantages. In particular, given the complexity of such arrangements, such arrangements lack compactness. For example, portions of the water pumps or associated components (e.g., manifolds associated therewith) can protrude out of the side of the outboard motor/engine or otherwise extend or be arranged in inconvenient manners. Also, the parts count of such water pump arrangements can be high. Further, durability of such arrangements can be limited, due to the use of fan belts and other components.
In addition to the above considerations, in contrast to many fuel systems developed for fuel injected engines in non-marine applications, where fuel is managed so as to be largely or mostly consumed by the engine but yet a portion of the fuel can be returned back to the fuel tank, conventional outboard motors typically have fuel systems that have been uniquely developed to pull fuel from a boat's fuel tank system and consume the fuel within the outboard motor's engine without returning fuel to the boat. In many fuel systems, there is a desire to be able to return fuel to a fuel tank particularly to allow for “excess” fuel output by a pressure regulator of the fuel system (serving to regulate fuel pressure) to return to the fuel tank. However the return of fuel to a fuel tank is viewed as problematic in marine applications in the case of an undetected leakage of fuel (e.g., because of disconnection of a fuel line) in the return circuit since, if such a leakage were to occur, the engine could continue to make power and propel the craft in spite of the fact that fuel is being lost into the boat without being delivered to the fuel tank. Indeed, such a problem can be difficult to detect as it does not immediately affect boat operation. Further, it has also been found that if leakage occurs on the supply side where fuel is being drawn into the engine, air or water is most likely entrained in the fuel line as the pressure in the fuel line on the supply side is depressed below atmospheric pressure, thereby enabling flow into the line, which can soon affect engine performance. Therefore, outboard motors that are mounted outside the rear of the vessel (i.e., mounted on the transom) have been developed with fuel systems that draw fuel into the engine, but without returning the fuel back across the transom into the boat.
Further in regard to fuel systems, it is also known to employ a vapor separator device or vapor separating tank (“VST”) within a fuel injected engine for drawing fuel into the engine without returning fuel to the fuel tank. Such VSTs are equipped with fuel pump(s), fuel filter(s), and a working volume of fuel that is required to supply fuel to the pump(s). This working volume of fuel is either vented or unvented to atmospheric pressure. VSTs separate air from fuel in the working volume of fuel, thus supplying liquid fuel to the fuel pump and venting the vapor or air (that occurs due to pressure depression in the supply line) out of the working volume of fuel. If air (vapor) is entrained in the fuel, to measurable extents, the fuel pump cannot maintain fuel flow or pressure. Fuel temperature can also cause vapor creation and, for at least this reason, many cooling devices have been incorporated into vapor separating tanks (“VSTs”) as fuel temperature now causes vapor according to the vapor pressure of the fuel. Aside from the use of such VSTs, the other known method of eliminating vapor, other than venting it out to atmosphere, involves pressurizing the working volume of fuel. In general, therefore, conventional VSTs either vent air out of the system or pressurize the fuel in the system in order to reliably deliver pressurized fuel to the engine.
Existing types of VSTs more particularly include (1) VSTs that are mechanically-switched (float-needle seat system), (2) VSTs that are electrically-switched, and (3) VSTs that are proximity-switched. A mechanically-switched VST often includes the following operational features or characteristics: (a) a high vacuum lift pump draws fuel from the onboard tank to the outboard; (b) fuel is delivered into a float chamber; (c) a float is lifted when there is a sufficient level of fuel in the float chamber; (d) the float acts upon a needle and seat which shuts off the incoming fuel; (e) the high pressure pump draws fuel from the float chamber and delivers it to a regulator; (f) the regulator allows a set pressure of fuel to pass and returns the excess to the float chamber; and (g) pressurized fuel exiting the high pressure pump is ready to be consumed by the engine. By comparison, an electrically-switched VST typically includes many of the aforementioned features of a mechanically-switched VST, but differs in that a diaphragm lift pump of the mechanically-switched VST will typically be replaced with an electric pump in the electrically-switched VST and, additionally, the float actuates an electrical switch opening the power circuit stopping the lift pump when the float chamber is full. This type of system can be made to operate without venting the float chamber to atmosphere, as the float and switch do not need an atmospheric reference. Lastly, proximity-switched VSTs typically include many of the same features or characteristics of mechanically-switched and electrically-switched VSTs, but further include a proximity switch on the float valve, or an ultrasonic device that indicates fluid level in the “float chamber” thereby interrupting the flow of the low pressure pump to halt the overfilling of the float chamber or working fuel volume.
Additionally, outboard motors have classically been designed to incorporate two cycle engine technology in a number of aspects. As two cycle engines did not require a captive lubricant compartment from which to draw lubricant or to which to return lubricant (from and to locations within the engine), in such engines the lubricant (typically oil) was added to the fuel in prescribed ratios and consumed through the course of normal operation. Yet as emissions regulations have become more stringent, the two-cycle engine, with its inherent disadvantage of hydro-carbon emissions, has given way to the four-cycle engine. With this transition in engine technology came the need for an oil sump from which the engine could pump and return lubricant. As outboard engines have historically been constructed with the engine being vertical in orientation, that is, with the crankshaft extending vertically, the oil sump has been mounted below the engine in a compartment not common to the crankcase. The sump additionally has been configured so that the oil will not flood into the engine as the engine is trimmed, that is, rotated about a horizontal axis perpendicular to the axis of propulsion. Thus, for many conventional outboard motors with such a vertical configuration (vertically oriented such that the crankshaft is vertically mounted) traditionally have included these additional characteristics: (1) sump mounted below the engine; (2) the engine crankcase communicates to the sump, but is not integral with the sump; (3) the sump has a geometry that is tall and thin; (4) the sump will not allow the engine to fill with oil when trimmed to an extent, such as approximately 70 degrees from horizontal; and (5) cylinders face aft and are tilted toward vertical when trimmed, preventing them from filling with oil should any oil be left in the engine during or after tilting.
Notwithstanding the traditional prevalence of vertically-configured outboard motors, horizontally-configured outboard motors (that is, outboard motors having a horizontally-oriented engine with a horizontally-extending crankshaft) have arisen that have somewhat different features, including: (1) an oil sump which is integral with the crankcase; (2) cylinders that are generally vertically oriented (or in the case of a V-type engine, oriented between 30 to 60 degrees from vertical); and an (3) an oil sump that is long, narrow, and shallow. Given this arrangement, when the engine is mounted in an outboard configuration and tilted (as described above in relation to vertically oriented engine), the engine oil pours out of the oil sump and into the crankcase of the engine. Consequently, oil that enters the crankcase can run into the cylinders as one or more of the cylinders have rotated to a near horizontal position. Yet oil that enters a cylinder can potentially be detrimental to the engine, as it can result in bending of the connecting rods due to hydraulic locking the engine, particularly if enough oil enters the combustion chamber and is acted upon by the piston.
Therefore, in view of the above, it would be advantageous if an improved outboard motor for use with marine vessels, and/or systems or components thereof, and/or methods or processes for operating or using same (and/or related methods or processes for manufacturing such an outboard motor, or systems or components thereof), could be developed that addressed one or more of the above concerns and/or provided one or more other or additional advantages.